Method for debristling animal skin

ABSTRACT

A variety of compositions and methods for removing hair from animal skin are disclosed. The methods can include heating the skin and applying force to the skin to remove hair. The methods can further include applying an adhesive comprising a wax and a resin to the skin, allowing the adhesive to solidify, and applying force to the adhesive.

This is a continuation of application Ser. No. 12/650,810, filed Dec.31, 2009, and claims the benefit of U.S. Provisional Application No.61/142,310, filed Jan. 2, 2009, all of which are incorporated herein byreference.

The present disclosure relates generally to preparing animal skin, andmore particularly, to a method for removing hair or bristle from animalskin.

Animal skin can be used for a variety of medical applications, includingthe production of tissue matrices or other grafts for repair,regeneration, and/or augmentation of human tissues. In many cases, it isdesirable to remove bristle or hair from animal skin as part of theproduction of grafts or implants derived from the skin. However, removalof the hair or bristle should not damage or alter the skin in such a waythat the desired mechanical, biological, or chemical properties are notpresent in the final implant or graft materials. Accordingly, methodsfor removing hair or bristle from animal skin are needed.

SUMMARY

In some embodiments, a method of removing hair or bristles from ananimal skin is provided. The method comprises heating the skin andapplying friction to the skin in an area of the skin containing hair orbristle to remove the hair or bristle from the skin, wherein the skin isheated to a temperature range that allows the hair or bristle to beremoved by friction, but has a maximum temperature and heating time thatdoes not damage the dermal extracellular matrix of the skin.

In some embodiments, an adhesive composition is provided. The adhesivecomposition comprises about 15% to about 20% by weight of a polyetherand about 80% to about 85% by weight of a polyamide. In someembodiments, a method for removing hair or bristle from an animal skinis provided. The method comprises providing an animal skin containinghair or bristle on a surface of the skin, contacting the at least onesurface with the adhesive, and applying a force to the adhesive toremove at least part of the adhesive composition to remove at least partof the hair or bristle from the skin.

All publications, patent applications, patents and other referencesmentioned herein are incorporated by reference in their entirety. Thematerials, methods, and examples disclosed herein are illustrative onlyand not intended to be limiting. Other features and advantages of theinvention, e.g., methods for debristling animal skin, will be apparentfrom the following description, from the drawings and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute partof this specification, illustrate several embodiments of the inventionand together with the description, serve to explain the principles ofthe invention.

FIG. 1A is a system for removing hair or bristle from an animal's skin,according to certain embodiments.

FIG. 1B is a side-end view of the system for removing hair or bristlefrom an animal's skin, according to certain embodiments.

FIG. 1C is a side-end view of the system for removing hair or bristlefrom an animal's skin, according to certain embodiments.

FIG. 2 is a flow chart illustrating a process for removing hair orbristle from an animal's skin, according to certain embodiments.

FIG. 3 is a flow chart illustrating a process for removing hair orbristle from an animal's skin, according to certain embodiments.

FIG. 4 is a system for removing hair from an animal skin, according tocertain embodiments.

DETAILED DESCRIPTION

Reference will now be made in detail to the certain exemplaryembodiments according to the present disclosure, certain examples ofwhich are illustrated in the accompanying drawings. Wherever possible,the same reference numbers will be used throughout the drawings to referto the same or like parts.

In this application, the use of the singular includes the plural unlessspecifically stated otherwise. In this application, the use of “or”means “and/or” unless stated otherwise. The use of the term “portion”may include part of a moiety or the entire moiety.

The section headings used herein are for organizational purposes onlyand are not to be construed as limiting the subject matter described.All documents, or portions of documents, cited in this application,including but not limited to patents, patent applications, articles,books, and treatises, are hereby expressly incorporated by reference intheir entirety for any purpose.

As used herein, the terms “hair” and “bristle” may be usedinterchangeably. “Hair” and “bristle” will be understood to mean animalhair, whiskers, fur, or any other hair-like structure present on animalskin.

The term “animal skin” will be understood to refer to a portion or allof an animal's skin, including a portion or all of an animal's dermaland epidermal layers, whether still attached to a part or all of theanimal's body, or after having been removed from the animal's body.“Animal skin” may be used interchangeably with “animal hide.”

In some embodiments, the present disclosure provides a method andapparatus for removing hair or bristle from animal skin. In someembodiments, the method can include changing the temperature of theanimal skin and applying force to the hair or bristle to remove the hairor bristle from the animal skin. In some embodiments, the force isapplied by applying friction to the skin at a region of the skincontaining hair or bristle. In some embodiments, the skin is heated to atemperature range that allows the hair or bristle to be removed byfriction, but has a maximum temperature and heating time that does notdamage the extracellular matrix of the skin.

In some embodiments, the present disclosure provides an adhesivecomposition that can be used to remove hair from animal skin. In someembodiments, the adhesive comprises a wax component and a resincomponent. In some embodiments, the adhesive composition can include apolyether and a polyamide. In some embodiments, the about of the waxcomponent and the amount of the resin component will be selected toproduced certain properties. In some embodiments, the amount of the waxand resin is selected to allow blending of the wax component with theresin component. In some embodiments, the amount of the wax and resin isselected to provide sufficient mechanical strength when solid to removehair or bristle, but to allow sufficient flexibility to apply the moltenmaterial to the skin at a temperature that does not damage the skin andto allow the material to be pulled from the skin. In certainembodiments, the present disclosure provides methods for removing hairfrom animal skin including applying an adhesive to the skin, allowingthe adhesive to solidify, and removing the adhesive by applyingmechanical force to the adhesive.

In certain embodiments, the present disclosure provides methods forremoving hair from animal skin including heating the animal skin to adesired temperature and applying force to the hair or bristle to removethe hair or bristle from the animal skin, followed by applying anadhesive to the skin, allowing the adhesive to solidify, and removingthe adhesive by applying mechanical force to the adhesive. In certainembodiments, the present disclosure provides methods for removing hairfrom animal skin including applying an adhesive to the skin, allowingthe adhesive to solidify, and removing the adhesive by applyingmechanical force to the adhesive, followed by heating the animal skin toa desired temperature and applying force to the hair or bristle toremove the hair or bristle from the animal skin.

The animal skin can be derived from a variety of different animals,depending on the type of graft to be produced. In some embodiments, theanimal can include a pig, the skin of which may be used to produceporcine dermal tissue matrices. However, the methods of the presentdisclosure can be used to remove hair or bristle from any mammaliansource.

FIG. 1A is a system for removing hair or bristle from an animal's skin,according to certain embodiments, and FIG. 1B is a side-end view of thesystem for removing hair or bristle from an animal's skin, according tocertain embodiments. In some embodiments, the system includes a chamber10 that can be used to control the temperature of the skin 12 of ananimal 14 from which hair 22 is to be removed. As shown, the entireanimal 14 may be placed in the chamber 10 during hair removal. In someembodiments, only a portion of the animal 14 may be placed in thechamber. In certain embodiments, the skin 12 or a portion of the skin 12may be removed from the animal's body and may be placed in the chamberduring hair removal.

In some embodiments, the temperature inside the chamber 10 is controlledto heat the skin 12 to a temperature range that allows the hair 22 orbristle to be removed by applying force to the hair 22, but has amaximum temperature and heating time that does not damage the dermalextracellular matrix of the skin. In some embodiments, the skin isheated to a temperature between about 53° C. and about 56° C. In someembodiments, the skin is heated to a temperature between about 53° C.and about 56° C. for a maximum of about 15 minutes. In some embodiments,the skin is heated to a temperature between about 53° C. and about 56°C. for a maximum of about 15 minutes. In certain embodiments, the skinis heated to about 54° C. for about 10 minutes. In certain embodiments,the skin is heated to no more than 60° C.

In some embodiments, the chamber 10 can be filled with a fluid 18, suchas water, and the temperature of the fluid can be controlled to heat theskin 12 to the desired temperature for hair removal. In someembodiments, the skin 12 is submerged in the fluid after the temperatureof the fluid is at the desired temperature. In some embodiments, theentire animal body or a portion of the animal body attached to theportion of skin that will be used to make a tissue graft or implant willbe submerged in the fluid.

The temperature of the chamber 10 can be controlled using a number ofmethods. In some embodiments, a heater 26 is in fluid communication withthe chamber 10 and controls the temperature of the interior of thechamber 10 or fluid 18 within the chamber 10. In some embodiments, theheater is configured to include a feedback mechanism to allow automaticcontrol of the temperature within the chamber to a desired temperaturerange.

In some embodiments, isolated portions of animal skin may be heated to adesired temperature. For example, in various embodiments, a portion ofthe animal skin can be heated by applying heat from an external source(e.g., air or light) to heat a portion of the skin, without submergingthe skin in a chamber. Force can be applied to hair or bristle locatedon the skin that is heated.

In some embodiments, after the skin 12 is placed in the chamber andreaches the desired temperature, force can be applied to the hair 22 toremove the hair 22 from the skin 12. In some embodiments, the force isapplied by applying friction to the skin 12 in one or more regionscontaining hair 22. In some embodiments, the animal 14 or skin 12 (ifthe skin is not attached to a portion of an animal body) is moved withinthe chamber 10 and is contacted with one or more rollers 34 or otherbodies. For example, as shown, the animal 14 can be rotated within thechamber using a rod 30 or other holding mechanism. In some embodiments,the skin 12 contacts the roller 34 during movement, thereby removing thehair 22.

In some embodiments, the rollers 34 may be mobile. For example, as shownin FIG. 1B, the rollers 34 may rotate or move relative to the skin 12,and when in contact with the skin, will apply friction to the skin 12 toremove the hair 22. In some embodiments, both the skin 12 and rollers 34are moved and/or rotated. In other embodiments, only one of the skin 12and rollers 34 are moved during hair removal. In some embodiments, therollers can include a surface that produces friction but does not damagethe skin substantially. In various embodiments, the rollers 34 can beproduced with surfaces including silicone, felt, polyethylene nap (e.g.,paint rollers), aluminum (e.g., splined aluminum), and stainless steel.

In other embodiments, the skin 12 or animal 14 can be held in place andor moved within the chamber 10 without causing trauma or damage to theanimal's body. For example, FIG. 1C is a side-end view of the system forremoving hair or bristle from an animal's skin, according to certainembodiments. As shown, the system again includes a chamber 10′ that maybe heated to a selected temperature. In some embodiments, the chambercan include a fluid 18 that is heated to a desired temperature. In someembodiments, the skin 12 or animal 14 is placed on a series of slottedsupports 38. In some embodiments, the supports 38 can close at leastpartially onto the animal 14 or skin to hold the animal 14 and skin 12in place. Further, in some embodiments, the supports may move to movethe pig relative to surfaces of rollers 34′ or other objects configuredto apply force to remove hair 22 or bristle from the skin 12.Alternatively or additionally, in some embodiments, the rollers 34′ canmove, as described with reference to rollers 34, of FIGS. 1A and 1B. Insome embodiments, the rollers 34′ will be positioned between thesupports 38.

FIG. 2 is a flow chart illustrating a process for removing hair orbristle from an animal's skin, according to certain embodiments. Asdescribed above, the chamber 10, which may contain a liquid 18, is firstheated to the desired temperature, as shown at step 200. After heatingthe interior of the chamber 10 or liquid 18 within the chamber 10, theskin is placed in the chamber 10, as shown at step 210. Next, force isapplied to the hair 22 to remove the hair 22 from the skin 12.

As described above, in some embodiments, the hair 22 may be removedwhile still attached to part or all of the animal 14. In someembodiments, the method is performed using a whole animal carcass.Therefore, in some embodiments, part or all of the skin is removed fromthe animal carcass after hair removal, as shown at step 230. After hairremoval, and subsequent to removal of skin from the carcass, the skinmay be processed to produce a decellularized tissue matrix, as shown atstep 240.

In some embodiments, the disclosure provides an adhesive composition(for use in removing hair or bristle from a mammalian skin sample)comprising a wax component and a resin component. In certainembodiments, the present disclosure also provides methods for removinghair from animal skin including applying the adhesive to the skin,allowing the adhesive to solidify, and removing the adhesive by applyingmechanical force to the adhesive.

In various embodiments, the adhesive composition can have one or more,or all, of the following physical and chemical properties: (i) a waxportion in the adhesive is capable of changing state at a lowertemperature (e.g., about 42° C. or less, about 38° C. or less, about 34°C. or less, about 30° C. or less, about 26° C. or less, or about 22° C.or less) than the resin portion alone (about 85° C.), which allows theadhesive to set quickly yet exhibit poor conduction heat transfercharacteristics; (ii) the adhesive provides a strong grip on the hair orbristles when the hair or bristles are encased in a solid plastic sheetof the hardened adhesive; (iii) the composition is hydroscopic and thusany moisture latent in the hair or bristles is absorbed by the adhesive;(iv) deposition of an insulating film of water-soluble wax upon the roomtemperature dermis is automatic and allows for filling of follicle holeswith wax where bristles have been removed in previous passes; (v) theadhesive is flexible enough to bend during the removal phase withoutcracking, resulting in a consistent peeling profile to remove thebristle from the skin on a continuous sheet of cooled adhesive; (vi) theadhesive is compatible with a thick polypropylene mesh (e.g., TENAXBrand ¾″ hex (Tenax, Baltimore, Md.)), which allows for augmentation fora first “pull” of bristle from the skin; (vii) the individual componentsof the adhesive are suitable for use with tissues intended fortransplantation surgery; and (viii) the adhesive allows for a thoroughmethod of bristle or hair removal without substantial damage to thedermal layer of the skin. Further, in some embodiments, the adhesive isformed from only biocompatible components, so that any chemicalsabsorbed by the skin from the adhesive during hair removal are notharmful if left within a graft or implant produced from the skin.

In some embodiments, the wax component of the adhesive can be apolyethyleneglycol (PEG), which can have an average molecular weight ofabout 600 daltons to about 3000 daltons. For example, a PEG can have anaverage molecular weight of about 600 daltons, about 800 daltons, about1450 daltons, about 1500 daltons, about 2000 daltons, about 3000daltons, or mixtures of any of the foregoing. One exemplary PEG usefulin the adhesive solutions is a commercially available PEG, CARBOWAXSENTRY 1450, which is manufactured by the Dow Company.

In some embodiments, the resin component can be a polyamide resincomprising fatty polyamides made by the condensation of functionalamines and polybasic acids (which can be obtained from unsaturatedvegetable or tree or other plant oil acids or esters). In someembodiments, the resin of the adhesive composition can be avegetable-oil based nylon such as MACROMELT 6071 or MACROMELT 6072(Henkel Adhesives Co.).

In some embodiments, the resin in the adhesive can be selected based onits Vicat softening point to molecular weight ratio. As used herein, the“Vicat softening point” (also known as Vicat Hardness) is thedetermination of the softening point for materials such as polyethylene,which have no definite melting point. It is taken as the temperature atwhich the specimen can be penetrated to a depth of 1 mm by a flat-endedneedle with a 1 square mm circular or square cross-section. An exemplaryVicat softening point is that of Macromelt 6071 or 6072.

In some embodiments, a solvent is added to the adhesive to produce adesired viscosity. For example, a solvent can be applied until theadhesive has a viscosity that allows the adhesive to be applied evenlyat the selected temperature, and produced a strong enough adhesive forhair removal.

In some embodiments, an adhesive composition can contain about 15% toabout 20% by weight of a PEG and about 80% to about 85% by weight of avegetable oil-based nylon. For example, an adhesive composition cancontain about 15% to about 20% of CARBOWAX SENTRY 1450 and about 80% toabout 85% by weight of MACROMELT 6071.

FIG. 3 is a flow chart illustrating a process for removing hair orbristle from an animal's skin, according to certain embodiments. First,the adhesive is applied to animal skin in an area with hair or bristle,as shown at step 300. The adhesive can be applied at a thickness ofabout 1 mm to about 3 mm. The adhesive can be applied with a brush,spray, or other technique that allows control of the placement of theadhesive. In some embodiments, the adhesive is applied when heated to atemperature sufficient to melt the adhesive, but low enough to preventdamage or other alteration to the dermal component of the skin.

In certain embodiments, the adhesive can be applied when the adhesive issoft or molten. In certain embodiments, the temperature is selected toallow the adhesive to be applied with a selected method, but having amaximum temperature that will not damage the skin, including the dermis.In some embodiments, the skin is heated to between about 85° C. andabout 110° C. In some embodiments, the glue is applied using a brush orother applicator, and may cool somewhat before being applied to theskin. In some embodiments, the glue is applied to the skin when at atemperature below a maximum selected to prevent damage to the skin. Insome embodiments, the maximum temperature is between about 90° C. andabout 95° C. In some embodiments, the temperature is about 92° C.maximum when contacting the skin.

After the adhesive is applied to the skin, the adhesive is allowed tocool to solidify, as shown at step 310. Then, a mechanical attachment isformed with the adhesive, as shown at step 320, to allow a force to beapplied to the adhesive to pull the adhesive from the animal skin, asshown at step 330, thereby removing hair or bristle attached to theadhesive.

In some embodiments, the skin is cooled by using an external cooler. Forexample, in one embodiment, the skin is cooled by augmented cooling(e.g., cold air) applied to at least one side of the skin. In someembodiments, the skin is cooled by augmented cooling only to theadhesive surface, and not to the skin portion opposite the adhesive(i.e., the dermal portion of the skin). In certain embodiments, a heatsink is not in contact with the portion of the skin facing away from theadhesive because such a heat sink may draw more heat into the skin.

The mechanical attachment can be formed in a number of ways. In someembodiments, an object is contacted with the adhesive while the adhesiveis still soft or molten, such that as the adhesive solidifies, theobject is embedded in the solidified adhesive. For example, in certainembodiments, a mesh formed of metal or strong flexible wire is placed ontop of the adhesive before the adhesive solidifies, and as the adhesivecools, the mesh is embedded in the adhesive. Subsequently, the mesh ispulled from the skin to remove the adhesive and hair or bristle from theskin.

In some embodiments, the mechanical attachment can be formed after theadhesive solidifies. For example, FIG. 4 is a system for removing hairfrom an animal skin, according to certain embodiments. In certainembodiments, the skin 412 is placed on a roller with the dermal side 414down, and the adhesive 416 facing outwards. The adhesive 416 is alignedwith the tangent surface of a second rotating body 410 (e.g., a clawroller) such that the surface 420 of the second body 410 intersects withthe apex 424 of the rotating path of the skin, wherein the advancingedge 428 of the cooled adhesive 416 can be rapidly pried away from theskin to thereby remove the hair or bristle from the surface of the skin412.

In some embodiments, the disclosure provides a method for determiningthe pliability of a tissue sample (e.g., a skin sample from which thehair or bristle has been removed, e.g., using a method describedherein). In some embodiments, the skin is subjected to a fold test,wherein the edge of the bald skin is gently folded over itself. In someembodiments, a fold of about 160° or more indicates a first level ofpliability of the bald skin and a fold of less than about 160° indicatesa second level of pliability of the bald skin.

Bald skin of the first level of pliability can be used, e.g., fortreatment of damaged firm tissues such as, but not limited to bone,cartilage, fascia, or tendon. Bald skin determined to have the secondlevel of pliability can be used, e.g., in the treatment of damaged softtissues such as, e.g., an organ (e.g., heart) or synovial tissue.

In certain embodiments, the method of removing hair using the adhesiveis used in conjunction with the method of heating the animal skin andapplying force to the hair. In some embodiments, hair is first removedby heating the animal skin and applying force to the skin, as describedabove. Subsequently, residual hair is removed using the adhesivecomposition. In some embodiments, the method of heating and applyingforce is performed while the skin is still connected to part or all ofthe animal body. Then, the skin is removed from the animal body, and theadhesive is used to remove residual hair.

As indicated above, skin prepared by any one of or combinations of themethods described above can be processed to produce dermal tissuematrices. The dermal tissue matrices can be used in procedures fortissue repair, regeneration, or augmentation. Various processes forproducing tissue matrices are known in the art. Such tissue matrices caninclude decellularized dermal matrices from which substantially all ofthe cellular components have been removed. Exemplary processes forproducing acellular tissue matrices are described in U.S. Pat. No.5,366,616 and U.S. patent application Ser. No. 10/896,594. Thedisclosures of which are incorporated herein by reference in theirentirety.

While the present disclosure has been described in conjunction with thedetailed description thereof, the foregoing description is intended toillustrate and not limit the scope of the disclosure, which is definedby the scope of the appended claims. Other aspects, advantages, andmodifications are within the scope of the following claims.

What is claimed is:
 1. A method of removing hair or bristles from ananimal skin, comprising: heating the skin by submerging the skin in aheated liquid; applying friction to the skin in an area of the skincontaining hair or bristle to remove the hair or bristle from the skin,wherein the skin is heated to a temperature range that allows the hairor bristle to be removed by friction, but has a maximum temperature andheating time that does not damage the dermal extracellular matrix of theskin wherein applying friction to the skin comprises rotating the animalbody within the liquid and contacting the rotating body with a surfaceto apply friction to the skin while the skin is submerged in the liquid.2. The method of claim 1, wherein the skin is heated to between about53° C. and about 56° C.
 3. The method of claim 2, wherein the skin isheated to about 54° C.
 4. The method of claim 1, wherein the skin isheated for less than about 11 minutes.
 5. The method of claim 1, whereinsubmerging the skin in the liquid comprises submerging an animal body inthe liquid.
 6. The method of claim 1, further comprising moving thesurface with respect to the skin.
 7. The method of claim 1, furthercomprising applying an adhesive to the skin; cooling the adhesive tosolidify the adhesive; and applying a force to the adhesive to pull theadhesive away from the skin and remove hair or bristle from the skin.